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论文类型：期刊论文

发表时间：2016-10-01

发表刊物：MATERIALS AND STRUCTURES

收录刊物：SCIE、EI、Scopus

卷号：49

期号：10

页面范围：4417-4424

ISSN号：1359-5997

关键字：C2S; Accelerated carbonation; Mineralogy; Si-29 MAS NMR

摘要：Accelerated carbonation of steel slag can reduce CO2 emissions as well as produce useful building material products. The C2S, the dominant mineral, varies with different steel slag processing methods. This work aims to examine the contribution of beta-C2S and gamma-C2S to strength development in the accelerated carbonation process and the microstructural changes induced by carbonation. Synthetic beta-C2S and gamma-C2S were compacted to cubes and exposed to CO2 (99.9 %) for accelerated carbonation. Carbonated C2S was analyzed by FT-IR, XRD, TG-DSC and NMR MAS. beta-C2S absorbs less CO2 than gamma-C2S, but presents a higher compressive strength. The CaCO3 formed in carbonated beta-C2S and gamma-C2S presents different polymorphs and thermal stabilities. Carbon dioxide reacts with C2S to form calcite and polymerized silica gel comprised of a Q(3) and Q(4) structure. However, for beta-C2S, in addition to Q(3) and Q(4), the hydration reaction was also accelerated and C-S-H (Q(1) and Q(2)) formed, thus leading to a higher compressive strength.